1. Field of Invention
The technical scope of the present invention is that of turrets intended for military vehicles and supporting an oscillating mass integrating a cannon.
2. Description of Related Art
The mounting of an oscillating mass onto a turret generally allows said oscillating mass to move in rotation around an axis that is fixed with respect to the turret, commonly called rotation in elevation. Moreover, the turret is itself able to rotate with respect to the vehicle, commonly called rotation in traverse. The latter rotation does not in general pose any particular problems. However, rotation in elevation poses problems that are difficult to solve for clearances of the gun cannon of around 100° with respect to the turret.
It is essential to insulate the turret with respect to the exterior so as to avoid any contamination and to ensure the evacuation of the combustion gases produced when the ammunition is fired and also naturally that of the empty cases or bases after the ammunition has been fired.
Furthermore, the oscillating mass is piloted and powered from the turret, which requires a communication to be established to ensure these functions whilst avoiding the propagation of gaseous combustion residues from the cannon to the turret.
Lastly, the oscillating mass is made to communicate with the exterior so that the combustion gases and the cases or bases may be evacuated. The oscillating mass also needs to be made air tight with respect to the exterior.
A turret has already been proposed that is insulated from the exterior by sealing means placed between this turret and the oscillating mass. For this, a seal is mounted on the turret surrounding the window required for the intended clearance of the oscillating mass. The contact of the seal lip on a cylindrical surface centered on the axis of rotation of the oscillating mass and connected to the oscillating mass ensures this sealing. However, this solution requires a radius for the cylindrical surface that is all the wider in that the clearance of the oscillating mass is substantial. Thus, for large clearances of the oscillating mass, for example 100°, the height of the turret presents a handicap for its bulk, for its discretion or for the mass of the assembly. Additionally, through friction, this seal produces a disturbance due to its resistance to the rotation of the oscillating mass. This disturbance is undesirable in that it forms the equivalent of a boundary friction that disturbs the accurate aiming of the oscillating mass on a target using an instruction transmitted by the servo controls to the elevation positioning means of the mass.